The Muser
Physics & Physiology of Color
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The Muser |
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The Color Musings Return to |
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Color is a complex thing. We usually refer to colors by their simple names, such as red, or blue. But of course, not all reds or blues look alike. Some are lighter or darker. Some seem richer, or more color-full . Some blues look a little greenish or purplish. So we invent other color names like mauve, or chartreuse, or burnt sienna, to make further distinctions between colors. Are there more precise and descriptive ways to talk about colors? Indeed, there are many workable methods of color classification. What all these methods share though, is that they recognize three characteristics of color. It always takes a minimum of three descriptors to classify a color. For example, we can create a color from three primary colors , and simply describe the amounts of each of the three primaries used. That is the basis for the C.I.E. Chromaticity system used by physicists and color technicians worldwide. But there are more descriptive, if less precise, classification methods that correspond more closely to how we see color. One such system was developed by A. H. Munsell between 1905 and 1929. Munsell described colors in terms of their hue, value, and chroma. Munsell classified colors into five major hues; today we use six for most purposes. His system wasn't mathematically based, and failed to account for some important phenomena of color vision. Still, his descriptive terms are quite useful. Any color can be described in terms of its hue, value and chroma. A dark brown color for example, would have a hue in the yellow-red region of the color wheel. It would have a low value (because it's dark). And it would have a low chroma. A light brown color would differ from the dark brown only in its value. © J. C. Adamson, 1997 |
Hue:  This color wheel shows the six major hues. There is an infinite number of hues between these colors. Hue is the most obvious characteristic of a color. There is really an infinite number of possible hues. A full range of hues exists, for example, between red and yellow. In the middle of that range are all the orange hues. Similarly, there is a range of hues between any other two hues. The color wheel shows each of the six colors with medium value, and relatively high chroma. Chroma:
These scales show red, magenta and blue hues in a range of chromas, all with medium value. Chroma is the purity of a color. High chroma colors look rich and full. Low chroma colors look dull and grayish. Sometimes chroma is called saturation. Value:
These scales shows low chroma red, magenta and blue, in a range of values. Value is the lightness or darkness of a color. Sometimes light colors are called tints, and dark colors are called shades. All high chroma colors must necessarily be medium in value (when created by subtractive color mixture). |
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